Využitelnost fosforu u drůbeže =:Utilization of phosphorus in poultry /

The aim of the dissertation was to determine the effect of exogenous phytase on the retention and ileal digestibility of phosphorus and calcium from the feed mixture with low level of inorganic phosphorus source and on the quality of egg shells in hens of the final hybrids of the carrier type. The dissertation work has been divided into two experiments. In the first part, the effect of phytase at level 150, 200, 250 and 300 FTU / kg on phosphorus and calcium retention without the use of phosphorus inorganic sources and on the weight of eggs, shell strength, shell weight, shell thickness and egg weight was evaluated. Phosphorus retention was positively influenced by the addition of exogenous phytase enzyme to the feed mixture at the indicated concentrations. Exogenous phytase did not have a definite effect on calcium retention. The egg shell quality, strength and thickness were positively influenced by the addition of exogenous phytase to the feed mixture at level 300 FTU / kg of the mixture. In the second part, the effect of exogenous phytase with activity of 300 FTU / kg on ileal digestibility of phosphorus and calcium from feed mixtures using inorganic sources of phosphorus in suboptimal doses (1.58 and 2.03 g / kg of non-phytate phosphorus, ie 2.6 and 3.0 g / kg of available phosphorus) and with different levels of calcium was evaluated. Phytase at 300 FTU / kg did not have a conclusive effect on the ileal digestibility of phosphorus and calcium. Higher ileal digestibility of phosphorus was found with a lower content of non-phosphate phosphorus in feed mixtures